This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A379423 #24 Jan 20 2025 00:47:39 %S A379423 1,3,7,21,56,168,504,1736,5208,15624,57288,171864,671832,2234232, %T A379423 7390152,32023992,96071976,450799272,1559322072,5860390536, %U A379423 20271186936,95118646392,385152551784,1236542403096,6182712015480,23494305658824,82848341007432,409295535424776 %N A379423 Least modulus k such that the multiplicative group modulo k is the direct product of n nontrivial cyclic groups. %C A379423 Compare with A102476. That sequence also measures the least modulus k with n nontrivial cyclic groups, but only using the rank, the minimal representation for each such k. For example, A102476(3) = 24 as (Z/24Z)* ≅ C2 x C2 x C2. However with this sequence a(3) = 21 as (Z/21Z)* ≅ C2 x C2 x C3. %H A379423 Asher Gray, <a href="/A379423/b379423.txt">Table of n, a(n) for n = 0..1000</a> %H A379423 Asher Gray, <a href="https://github.com/thegraycuber/least_modulus_with_n_cycles">Least modulus with n cycles</a>, Github repository. %H A379423 Asher Gray, <a href="https://youtu.be/jCfoeqmQNeQ?si=3OqfUkYdQ7-MYvR6">Sequences from Group Theory</a>, YouTube Video. %e A379423 a(2) = 7 because (Z/7Z)* ≅ C2 x C3. %Y A379423 Cf. A102476. %K A379423 nonn %O A379423 0,2 %A A379423 _Asher Gray_, Dec 22 2024